Joss Whedon sees 'Avengers 2' as a "marvellous challenge" following the success of his 2012 blockbuster, 'Avengers Assemble'

The screenwriter and director is set to deliver the sequel to last year's 'Avengers Assemble' and while he aims to make the follow-up "different", he understands its success may not be as high as the previous Marvel film.

He told Total Film magazine: "I am not going to try and match the box office of the first one because that would be bonkers. There is a certain level of safety - because now people know about 'The Avengers' and they like the characters so it probably won't completely crash and burn.

"But you don't want to just get by and do something that is merely okay. If I am going to dedicate three years of my short life to this then I want to do something that I have never done before.

"So I think of 'The Avengers 2' as a glorious challenge - it is a sequel, yes, but how can it be different?"

Returning stars from the first instalment are said to be Chris Hemsworth as Thor, Robert Downey Jr. as Iron Man, Scarlett Johansson as Black Widow, Jeremy Renner as Hawkeye, Samuel L. Jackson as Nick Fury and Chris Evans as Captain America.

Joss, 48, is also working on US TV series 'S.H.I.E.L.D' after blowing Disney bosses away with the 2012 blockbuster.

Announcing the development towards the end of last year, Disney said in a statement: "Joss Whedon has signed an exclusive deal with Marvel Studios for film and television through the end of June 2015.

"As part of that deal, Whedon will write and direct Marvel's 'The Avengers 2' as well as help develop a new live action series for Marvel Television at ABC. He will also contribute creatively to the next phase of Marvel's cinematic universe."

'The Avengers 2' is scheduled to begin filming at the UK's Pinewood-Shepperton studios early next year.

Ultron, an artificial intelligence created by Tony Stark (Downey Jr) to keep the peace, goes rogue and decides to kill off the Avengers. Barely logical but impressively entertaining superhero fun; Johansson and Olsen are central to the action and Whedon's script is strong, snappy and irreverent, but it doesn't have much…